Combined soap and synthetic detergent bar



y 1950 D. E. MARSHALL 2,508,578

COMBINED SOAP AND SYNTHETIC DETERGENT BAR Filed May 5, 1944 4 Sheets-Sheet 1 APPRECIABLE TIME REQUIRED FOR SULFATED SYNTHETIC DETERGENT SOLUTION T0 LESSEN FOAM OF SODIUM TALLOW SOAP AT 46C ANDFH 8.0.

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COMBINED SOAP AND SYNTHETIC DETERGENTv BAR Filed May 5, 1944 4 Sheets-Sheet 5 [NYE/V702 Do/441,0 6'. MHESHHAL H42 H Tree/vise M y 23, 1950 D. E. MARSHALL 2,508,578

comaxmsn SOAP AND SYNTHETIC DETERGENT BAR 4 Sheets-Sheet 4 Filed May 5, 1944 Fox 771: fie/vi HrroE/VE Vs Patented May 23, 1950 UNITED STATES PATENT OFFICE COMBINED SOAP AND SYNTHETIC DETERGENT BAR Donald E. Marshall, Summit, N. J., assignor, by

order of court, to Colgate-Palmolive-Peet Company, a corporation of Delaware Application May 5, 1944, Serial No. 534,182

6 Claims.

1 My invention relates to detergents, under which I class soaps which are salts of the fatty acids and the synthetic detergents which are not necessarily salts of the fatty acids. There have been developed a considerable number of sulfated synthetic detergents made by chemically treating from the skin and hair free of the scum which is characteristic of ordinary soap.

Several diiilculties, such as extreme solubility and extreme removal of the natural oils of the skin, have militated against the successful marketing of synthetic detergents for toilet use, which this invention overcomes as its object. Also, several shortcomings, such as scum forming suds,

harshness, and slipperiness, are present in conventional fine toilet soaps, which this invention improves as its object.

It has been recognized for some time that the advantages of synthetic detergents complement and improve the shortcomings of ordinary toilet soap, but every attempt to combine the two has been unsuccessful. My combination bar does do this successfully and produces a toilet bar which is superior to either synthetic detergent used separately or formulations where these materials are combined in a homogeneous unit.

Broadly speaking, my invention consists in providing the user with a toilet bar which, when used in the conventional manner, will be satisfactory and will excel ordinary soap in lather mildness, rinsing, and cleansing properties and, when used so as to get only synthetic detergent in the lather, or only soap in the lather, will please the discriminating user who understands the special properties of each detergent.

Further objects and advantages will be made evident heremaiter.

In the drawings, which are for illustrative purposes only,

Fig. 1 is a graph showing the influence of time on a mixture of soap and a synthetic detergent, the specific synthetic detergent employed being sodium lauryl sulfate;

Fig. 2 is a graph showing the detergency emciency of various proportions of soap and synthetic detergent in washing fabrics, the specific synthetic detergent employed being sodium lauryl sulfate;

Figs. 3 and 4 are views of one form of a cake embodying my invention.

Figs. 5 and 6 are views of an alternative form of cake;

Fig. 'I shows another alternative form of cake; and

Fig. 8 shows how the cake shown in Fig. '7 is assembled.

The synthetic detergents listed below are typical of those suited for use in this invention:

Chemical Name Typical Formula Sodium Lauryl Sulfate 0l1H23CH20S03Na CHIOH Sodium Laurie O 1HnOO0lHCHa0SmNa Sulfate Sodium Hydroxyethane Sulfonatex Monoglyceride 017113300 0 CHllCHzS ozNa Sodium Alkyl Benzene Su1fonate Sodium Alkyl Benzene Sulfonate..

Sodium Alkyl Sulfonate.... CgoH SosNa GQHBOCO-OHI Sodium Dihexyl Sulfosuccinate--.- CaHnO GO( JHS OaNa OSOyNa Sodium Secondary Tridecyl Sulfate. CaHu- G1Hu The term synthetic detergent" is employed to mean a surface active water-soluble alkali salt of an organic material which does not form waterinsoluble compounds with calcium and magnesium present in hard waters and which has the property of dispersing or dissolving insoluble calcium and magnesium soaps.

As illustrated by the above list, such synthetic detergents are usually sodium salts of long chain organic compounds containing sulfate or sulfonate groups but, as is well known, other groups may be employed instead of the sulfate or sulfonate groups to produce water-soluble surface active materials and other equivalent alkalies such as potassium can be employed instead of sodium. Many such synthetic products are now in general use, and many others are known or are in limited use.

Mixtures of soaps and sulfated synthetic de- 3 tar-gents may have only limited application in washing fabrics because of the lack of the slipperiness which soap solutions possess; this effect is shown clearly in Fig. 2.

However, this slippery characteristic is not a necessary factor to cleansing the skin or hair because the synthetic detergent, unlike soap, is very effective in breaking down the interface between water and the oil secretions of the skin, thus liberating the dirt. The lather characteristics are such that rinsing is noticeably improved by the absence of hard water scum, leaving the skin and hair feeling clean. The hands squeak when rubbed together, just as clean glassware squeaks when rubbed if free of soap scum.

The lather is very important to skin and hair cleansing because it serves as a vehicle to carry off the dirt particles, also because, psychologically, the public judges toilet soaps by this property. Mixtures of soap and sulfated synthetic detergents lather very poorly and less than if either were used alone; however, this effect is not a factor in the combination bar because in the few seconds used to wash hands or develop a lather in the tub or shower, this effect does not take place, as shown in Fig. 1. Actual consumer tests of my combination bar have borne out this fact by quick acceptance of the combination bars lather. These tests also show that once a consumer becomes accustomed to the clean rinsing properties of the combination bar, the consumer will find the slippery feel of soap lather and soap washed skin distasteful.

Furthermore, this combination lather prevents the formation of dirt rings on the porcelain wash bowl or tub and greatly reduces the hazard of slipping in the shower.

Broadly, my invention consists in providing the user with a cake of toilet soap containing separate pieces of soap and synthetic detergent, which are so incorporated in the cake that the user may use the soap without using any synthetic detergent or may also mix with the suds produced by the soap any desired proportion of suds of synthetic detergent.

Such a cake is shown in Figs. 3 and 4, in which the synthetic detergent 20 is secured to the soap 2| by a tenon 22. It is desirable that the interface 23 between the soap 2| and the synthetic detergent 20 be protected from seepage of water, and for this purpose I provide a calking groove za m the body of the synthetic detergent and force a calking lip of soap into this groove.

An alternate form of cake is shown in Figs. 5 and 6, in which a body of the synthetic detergent 25 is embedded in a cake of soap 2G, a calking groove 21 being provided in the detergent into which a calking lip of soap is forced. The calking lip is desirable largely to prevent moisture from escaping from the space at the interface of the soap and synthetic detergent. When the cake is in storage, such drying out tends to warp the cake and cause the synthetic detergent to separate from the soap. When in use and while kept wet by such use, the natural swelling of the cake protects the interface against such separation.

Another form of cake is shown in Figures 7 and 8, in which a semi-cylindrical block of soap 3!] has a dovetail groove extending lengthwise along its fiat face. A semi-cylindrical block of synthetic detergent 3| is provided with a dovetail tenon 32 extending from its flat face, and when the tenon is engaged with the dovetail groove in the soap block so as shown in Figure 8 a com- 4 posite cake is formed. A projecting ridge 33 is provided around the edge of the flat face of the soap block 30 to enable the user to secure a better grip of the composite cake.

One method of producing a cake embodying my invention is as follows:

A soap of the desired characteristics is produced by a saponification of fatty acids. The conventional method of producing such a soap is to treat a fat with caustic alkali, for example, caustic soda (NaOH), which releases glycerine and produces salts of the fatty acids. The soap is processed in the usual manner to produce the desired physical characteristics. The sulfonated or sulfated synthetic detergent may be produced by any known process, and the detergent may then be mixed with inert material such as water or super-fats to give it the proper milling body. The synthetic detergent is then milled and formed into a cake of the desired form, and the soap is then pressed or formed around the cake of synthetic detergent to produce the final cake.

In practice, both the soap portion and the synthetic detergent portion are milled and extruded through an orifice of a conventional soap plodder to form a bar of the desired section, which is then cut into portions having the desired volume. The firmer of the two bodies, which is usually the synthetic detergent portion, the warm soap being quite ductile and pliable, is then formed and may have the tenon 22 or other mechanical locking means formed thereon. The malleable or ductile portion is then formed around the harder portion. The calking groove is preferably formed in the hard portion, and this groove is filled by the calking lip as the malleable body is pressed into place.

The proportions shown in the drawings are suitable for only certain combinations of soap and synthetic detergent. The proportions were determined by trial and are dependent on the relative solubility in the soap and synthetic detergent used. The cake should be so proportioned that the synthetic detergent and soap are used in proportion to their relative volumes at all times. With a highly soluble detergent like some of the sulfated synthetic detergents, a relatively large volume of detergent is used. The result sought is to produce bodies of soap and synthetic detergent of such relative volume that this relationship remains constant as the cake is used, and the final cake when greatly reduced in volume by such use still has approximately the same relative volumes of soap and detergent.

The above-described cake or bar has many advantages, which will be described in order.

(a) The bar has very good lathering properties. The initial lather is largely due to the soap, although the addition of synthetic detergent to soap tends to lessen the foam of the soap lather. Fortunately, as shown in Fig. 1, the detergent has very little effect on the soap lather during the first five seconds. As a result, the user works up a fine initial lather. The synthetic detergent tends to prevent calcium recipitation due to hard water, and the lather is not slimy and has a feel that is most desirable. In practice, the user of the dual bar can control the action of the lather to any desired degree; for example, by rubbing only the soap side of the bar, he gets a predominating soap lather; by rubbing the synthetic detergent side, he gets a detergent lather; and. by a proper combination of these vtwo actions, he gets any desired lather combination.

(b) Although the dual bar above described is a very efficient dirt remover, it is less irritating to the Skin than the average toilet soap, as shown by the controlled biological tests shown in the following table:

Degree of skin irritation by patch tests Synthetic ,'Soap; Subjects Initial 2 S ffjf, Detergent Synthetic g Alone Detergent P. L 18 1 1 0 D. O 31 1 0 1 T. G 18 0 0 0 B. L 34 1 0 1 S. N. 27 0 1 0 L. G- 19 1 0 0 S. F 28 2 0 l H. D 19 2 0 1 B. H--- 0 2 1 F. R 17 1 2 O E. L 20 0 0 0 D. Z- 19 1 D 0 R. F" I- 20 1 0 1 G, B... 18 2 0 1 S. F--- 17 1 U 0 G. B 20 0 1 (1 R. F 18 1 O 1 M. Z 2O 1 0 0 H. A 17 3 0 1 E. K 19 1 0 1 G. Y 17 1 1 0 R. S 19 U 1 0 K. H 0 0 1 B. H 14 0 0 0 R. P 19 2 0 0 25 people 23 9 11 wrinkling,

(c) The principal defects of soap as a cleansing agent for toilet use are that it does not cleanse thoroughly and in hard water forms an insoluble precipitate which adheres to the skin and is itself a dirt and a dirt collector. The principal defect of the synthetic detergent is that it tends to remove the natural oils from the skin, leaving the skin very dry. When used with or subsequent to the use of soap lather, the detergent not only cleanses better than soap, but it also prevents the formation of and tends to disperse in suspension the calcium and other precipitates formed by the soap. By an intelligent use of the dual bar, the user may get almost any degree of final dryness with the proper cleansing action.

(d) Since the detergent has a marked dispersing action on dirt particles and soap precipitates, it prevents these particles and precipitates from adhering to the skin, and they are readily removed by rinsing. After such rinsing, the skin feels, and is, absolutely clean and does not have the slimy 0r scummy feeling that continued rinsing will not remove if soap alone is used. Wash basins, bath tubs, and showers are also rinsed clean, no scum or precipitate being left on the surface,- particularly if the surfaces are washed with detergent lather after use and before rinsing.

(e) A cake of detergent alone is highly soluble in water and wastes away rapidly if habitually left in a wet soap dish. This solubility is a necessary characteristic if good detergent action is desired, but bars made solely of synthetic detergent are very short-lived'if used in the manner in which soap bars are now used and placed in wet soap dishes. The soap portion of the dual bar surrounds and protects the detergent portion from wastage both in the soap dish and in use.

In using either of the cakes illustrated, the user may make lather by contacting both the soap and the synthetic detergent at the same time, or may first make a lather containing apreponderance of soap and then remove the soap by synthetic detergent.

I recognize that composite cakes have been produced by mixing particles of soap and particles of synthetic detergent, but I believe I'arn the first to produce a cake in which the soap and synthetic detergent are present in the cake in discrete and distinct masses, each and all of which form a portion of the outer surface of the cake in such positions that either soap or synthetic detergent, or any proportion of either, may be used as desired. This is necessary if the user desires to selectively mix soap and synthetic detergent in the lather'produced.

This application is a continuation-in-part of my application Serial No. 462,513, filed Octobe 19, 1942, and now abandoned.

I claim as my invention:

1. A composite detergent cake comprising a body of water-soluble fatty acid soap having an exposed surface for producing a lubricating and grime disassociating lather with water, said soap lather precipitating insoluble soaps due to any hardness of the water, and a body of solid water-soluble synthetic detergent selected from the group consisting of anionic sulfated organic synthetic detergents and anionic sulfonated organic synthetic detergents integrally secured to said body of soap and having an exposed surface for producing an insoluble soap dispersing and water and oil interface breaking lather, said synthetic detergent having the characteristic that its lather promotes rinsing of said insoluble soaps and disassociated grime.

2. A composite detergent cake comprising a. body of water-soluble fatty acid soap having an exposed surface for producing a lubricating and grime disassociating lather with water, said soap lather precipitating insoluble soaps due to any hardness of the water, and a body of solid watersoluble anionic sulfated organic synthetic detergent integrally secured to said body of soap and having an exposed surface for producing an insoluble soap dispersing and water and oil interface breaking lather, said synthetic detergent having the characteristic that its lather reacts with said soap lather to lessen both of said lathers after a time interval and promotes rinsing of said insoluble soaps and disassociated grime.

3. A composite detergent cake comprising a body consisting essentially of water-soluble fatty acid soap having an exposed surface for producing a lubricating and grime disassociating lather with water, said soap lather precipitating insoluble soaps due to any hardness of the water, and a body consisting essentially of solid watersoluble synthetic detergent selected from the group consisting of anionic sulfated organic synthetic detergents and anionic sulfonated organic synthetic detergents integrally secured to said body of soap and having an exposed surface for producing an insoluble soap dispersing and,

water and oil interface breaking lather, said synthetic detergent body having higher water solubility than said soap body, said soap body at least partially surrounding said synthetic detergent body to limit contact of water with said synthetic detergent body, said synthetic detergent having the characteristic that its lather promotes ,rinsing of said insoluble soaps and disassociated grime.

4. A composite detergent cake comprising a body consisting essentially of water-soluble fatty acid soap having an exposed surface for producing a lubricating and grime disassociating lather with water, said soap lather precipitating insoluble soaps due to any hardness of the water, and a body consisting essentially of solid watersoluble synthetic detergent selected from the group consisting of anionic sulfated organic synthetic detergents and anionic sulfonated organic synthetic detergents integrally secured to said body of soap and having an exposed surface for producing an insoluble soap dispersing and water and oil interface breaking lather, said synthetic detergent body having higher water solubility than said soap body, said soap body at least partially surrounding said synthetic detergent body to limit contact of water with said synthetic detergent body, said synthetic detergent having the characteristic that its lather reacts with said soap lather to lessen both lathers after a time interval and promotes rinsing of said insoluble soaps and disassociated grime.

5. A composite detergent cake comprising a body of water-soluble fatty acid soap having an exposed surface for producing a lubricating and grime disassociating lather with water, said soap lather precipitating insoluble soaps due to any hardness of the water, and a body of solid watersoluble anionic sulfonated organic synthetic detergent integrally secured to said body of soap and having an exposed surface for producing an insoluble soap dispersing and water and oil 8 interface breaking lather, said synthetic detergent having the characteristic that its lather promotes rinsing of said insoluble soaps and disassociated grime.

6. A composite detergent cake comprising a body of water-soluble fatty acid soap having an exposed surface for producing a lubricating and grime disassociating lather with water, said soap lather precipitating insoluble soaps due to any hardness of the water, and a body of solid watersoluble sulfated monoglycerides of soap-forming fatty acids integrally secured to said body of soap and having an exposed surface for producing an insoluble soap-dispersing and water-andoil-interface-breaking lather, said synthetic detergent having the characteristic that its lather promotes rinsing of said insoluble soaps and disassociated grime.

DONALD E. MARSHALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS FOREIGN PATENTS Country Date France Mar. 13, 1939 Great Britain of 1897 Great Britain Aug. 31, 1939 Number Number 

1. A COMPOSITE DETERGENT CAKE COMPRISING A BODY OF WATER-SOLUBLE FATTY ACID SOAP HAVING AN EXPOSED SURFACE FOR PRODUCING A LUBRICATING AND GRIME DISASSOCIATIONG LATHER WITH WATER, SAID SOAP LATHER PRECIPITATING INSOLUBLE SOAPS DUE TO ANY HARDNESS OF THE WATER, AND A BODY OF SOLID WATER-SOLUBLE SYNTHETIC DETERGENT SELECTED FROM THE GROUP CONSISTING OF ANIONIC SULFATED ORGANIC SYNTHETIC DETERGENTS AND ANIONIC SULFONATED ORGANIC SYNTHETIC DETERGENTS INTEGRALLY SECURED TO SAID BODY OF SOAP AND HAVING AN EXPOSED SURFACE FOR PRODUCING AN INSOLUBLE SOAP DISPERSING AND WATER AND OIL INTERFACE BREAKING LATHER, SAID SYNTHETIC DETERGENT HAVING THE CHARACTERISTIC THAT ITS LATHER PROMOTES RINSING OF SAID INSOLUBLE SOAPS AND DISASSOCIATED GRIME. 